261020569 has 2 divisors, whose sum is σ = 261020570. Its totient is φ = 261020568.

The previous prime is 261020549. The next prime is 261020581. The reversal of 261020569 is 965020162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 226352025 + 34668544 = 15045^2 + 5888^2 .

It is a cyclic number.

It is not a de Polignac number, because 261020569 - 2¹¹ = 261018521 is a prime.

It is a super-2 number, since 2×261020569² = 136263474882167522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 261020569.

It is not a weakly prime, because it can be changed into another prime (261020509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130510284 + 130510285.

It is an arithmetic number, because the mean of its divisors is an integer number (130510285).

Almost surely, 2^261020569 is an apocalyptic number.

It is an amenable number.

261020569 is a deficient number, since it is larger than the sum of its proper divisors (1).

261020569 is an equidigital number, since it uses as much as digits as its factorization.

261020569 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 261020569 is about 16156.1310034302. The cubic root of 261020569 is about 639.0844403715.

The spelling of 261020569 in words is "two hundred sixty-one million, twenty thousand, five hundred sixty-nine".